tTF/tTF-NGR characterization. (A,B) SDS-PAGE and Western blot analysis of tTF and tTF-NGR. (C) Ability of the fusion proteins to enhance the specific proteolytic activation of FX by FVIIa in the presence of phospholipids was evaluated by Michaelis-Menten analysis as described by Ruf et al.²²  The calculated Michaelis constants (K_m) of the hyperbolic parts of the kinetic curves were 0.2 nM (tTF) and 0.4 nM (tTF-NGR), respectively. Mean values of 3-fold assays are given with SD.